Breechblock operating mechanism with a torsion closing spring



March 1, 1949. w. SUMMERBELL ET AL 2,462,92@

BREECHBLOCK OPERATING MECHANISM WITH A TORSION CLOSING SPRING Filed Nov. 30, 1945 5 Sheets-Sheet 1 William EILLTI'ITI'IEThEl]. 5511] Weiss arch 1, 1949. w, SUMMERBELL ET AL 2,452,9ZQ

BREEGHBLOCK OPERATING MECHANISM WITH A TORSION CLOSING SPRING Filed Nov. 50, 1945 5 Sheets-Sheet 2 \A/llham Eummrarhell Elaul Weiss y 2% MM Moon; 5

Mamh 1949. w. SUMMERBELL ET AL 2,452,92Q

BREECHBLOCK OPERATING MECHANISM WITH A TORSION CLOSING SPRING Filed Nov. 30, 1945 5 Sheets-Sheet 3 W W m h 06 .m a w m E 4 I4 P I]? I vm m 3 March 1, 1949. w. SUMMERBELL ET AL BREECHBLOCK OPERATING MECHANISM WITH A TORSION CLOSING SPRING Filed Nov. 30, 1945 5 Sheets-Sheet 4 /7- 1L3? 3 ,ZJ WWM Z Willi am. Eummerball 4 5 am]. WEiSE March 1, 1949. w. SUMMERBELL ET AL 2,462,920

BREECHBLOCK OPERATING MECHANISM WITH A TORSION CLOSING SPRING Filed NOV. 30, 1945 5 Sheets-Sheet 5 a woe/1440115 William iummarball 55ml Weiss ww mw Patented Mar. 1, 1949 BREECHBLOCK OPERATING MECHANISM WITH A TORSION CLQSING SPRING William Summerbell and Saul Weiss, Washington, D. (3., assignors to the United States of America as represented by the Secretary of War Application November 30, 1945, Serial No. 632,098

(Granted under the act of MarchB, 1883, as amended April 30, 1928; 370 0. G. 757) '7 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to us of any royality thereon.

This invention relates to an improvement in the breechblock operating mechanism of guns having a sliding breechblock, such as the Armys 75mm. and 90 mm. guns of types in and M3; and the invention will be described in connection with such guns.

It'is the main purpose of the invention to provide breech operating mechanism in a gun of the type aforesaid wherein automatic closing of the breechblock is effected by a torsion coil spring.

A further object is to provide a mechanism in connection with such a spring whereby prior art constructions are simplified and wherein the torque normally eXterted by the aforesaid closing spring, may be temporarily relieved from the breech-closing shaft, to thereby enable easy and rapid assembly and disassembly of the breechoperating mechanism.

A further object is to provide a construction whereby the torque of a breech-operating torsion spring may be easily and rapidly adjusted.

Other objects and advantages will become apparent after a study of the following description in connection with the drawing wherein Figure 1 is an elevation of the closing device as applied to the breech ring of a '75 mm. gun,

Figure 2 is a side elevation of the same, Figure 3 is a section on the line 3-4; of Figure 2, Figure 4 is a longitudinal section on the line .,4 of Figure 1,

Figure 5 is a perspective view of the breechclosing spring housing,

Figure 6 is a perspective View ofv the bracket supporting the relieving pin,

Figure '7 is a perspective view of the breech closing spring,

Figure 8 is a perspective view of the operating crank,

Figure 9-is a front View of the clutch,

Figure 10 is a side view of the same,

Figure 11 is a perspective view of the plunger for controlling the operating spring tension.

Figure 12 is a perspective view of the breechblock operating shaft and its connection is with the breechblock, shown in phantom.

Figure 13 is a sectional detail View taken upon 1 The numeral l2 shows a well known form of breech ring as presently used on mm. tank guns in which the tube 13 of the gun fits bore lita, Fig. 4, and is secured therein by threads [21), the rear portion of the breech ring 12 being generally rectangular as seen at Fig. 1. The breechblock' it is of the vertical sliding drop block type and has a vertical rib, Ma, on each side, each of which slidably fits a corresponding vertical groove or channel 12a in the breech ring. See Fig. 14. Below and a little forwardly of the breechblock, the breech ring is provided with depending lugs l9 and Eda having transverse, aligned bores to journal the splined breech operating shaft it by mechanism subsequently described. Operating connection between the breechblock and breech operating shaft i6 is offected by a crank 38 comprising a sleeve 43 having an internally splined bore fitting the splined portion of shaft 18 and provided withan integral lever 5i. Figs. 4, 8, 12 and 14. The end of this lever has aligned crosshead pivots l2 upon each of which is journaled a crosshead 52a and 42b, Fig. 12. Each crosshead slidably engages a downwardly and rearwardly inclined slot, such as Mb and M c, Figs. 12 and 14, so that, on rotation of shaft 16, the breechblock it may be raised and lowered as will be readily apparent from inspectionof Fig. 14. Rotation of shaft 16 to lower the breechblock is effected in a well known manner when, as the barrel and breechblock move forwardly in returning to battery, the crank pin I 50. of crank operating lever l5 engages a cam ejector mounted upon the gun cradle. This cam ejector, not shown, corresponds in function and general manner of operation with pawl I, Fig. 3 of the patent to Meigs et al., 742,702, and need not be further described since it is well known and forms no part of the present invention.

Extractors 5i and 5-58 are slidably and pivotally carried by the breech ring. As shown at Figs. 12, 13 and 14, each extractor has aligned trunnions such as am and 511), Fig. 12, extending from opposite sides of its lower end. Each extractor is positioned between the breech ring and breechblock. Using extractor 51 as an example, and referring to Fig. 12, inner trunnion 51a rides in a generally vertical slot M0 in block it. The outer trunnion of each extractor engages in a generally arcuate slot such as 120, Fig. 13, formed in the breech ring !2. As the breechblock I 4 is moved downwardly as the gun returns to battery, the innerqextractor ,trunnions such as War, at first ride in the. straight vertical portions of breech?- block;slotssuch as. Mcand the, extractors remain,

motionless. When the breechblock nears its downward limit of travel and fully uncovers the cartridge case, the inner extractor trunnions ride in the upper, forwardly-curved portions of slots such as I40, whereby the lower ends of the extractors are forced forwardly, that is, to the right as indicated by the arrow in Fig. 13. The front cam edges 57c and 580 of extractors 51 and 58 then roll on the face of the breech recess and the upper lips 51d and 58d, engaged under the rim of the cartridge case, are forced rearwardly to draw the case out of the chamber.

When the breechblock reaches full open position, further motion is prevented by contact of the crank 15 with a stop surface, not shown, in the front of the breech recess. As shown at Fig. 13, for extractor 58, an extractor plunger 60 is slidably mounted in a hole drilled in breech ring l2 and is urged into engagement with its extractor 58, by a spring 61 backed by a hollow screw 62 threaded into a counterbore in the breech ring.

-A like and similarly mounted plunger is provided for extractor 51. When the breechblock reaches its lowermost position, the extractor plungers, under influence of their springs, push the inner extractor trunnions forwardly out of their grooves onto horizontal flat surfaces such as 14d, Fig. 12, of the breechblock. Since outer or breech ring extractor trunnions, 51b and 581), are coaxial with their breechblock is thus locked in lowered position.

When the next cartridge is rammed, the base of the cartridge case engages the extractors and forces the inner trunnions rearwardly off the fiat surfaces such as Md, previously mentioned, and into the extractor slots. As a result, the block is free to rise under the action of the breechblock spring. Extractor operating levers I1 and Hot are provided for operating the extractors to permit the breechblock to close without a cartridge being inserted therein. As shown at Fig. 13 for extractor 58, lever Ila is pivoted by a pin extending across a bore 64 which opens at one end into slot [2b and at its other end through the rear surface of the breech ring. One end of the lever projects into the slot, in the path of trunnion 58b while the other end of the lever projects to the exterior of the breech ring, as clearly shown at Fig. 1. Lever I1 is similarly mounted and acts upon extractor 51. By pressing upon the projecting ends of these levers, the outer trunnions may be forced inwardly off the flat surfaces such as [401 and into the extractor slots in the breechblock, whereby the block may move upwardly to closed position. Fig. 14 shows a shell S being extracted as the inner extractor trunnions ride in the curved portions of the breechblock extractor slots. From Fig. 3, it will be noted that lever I5 is connected with shaft I6 by reason of the splined bore of its hub fitting the end of the shaft. This hub is prevented from axial displacement in one direction by engagement with sleeve 43 of crank 48, and in the other direction by a locking pin 23 passing through a hole in lug l9 and a channel 65 in the hub.

At the right end, shaft I6 is smooth and is journaled in a bushing or spring housing 24, preferably made of bronze, within which housing the spring 18 acts to close the breech when the breech block i4 is released for such movement. A recess 25 is provided in the said housing 24 to accommodate the adjacent end of the spring IS. The bushing 24 is fixed against axial displacement by a screw 26 threaded into a radial hole in lug l9a and having its end engaging in a circumferrespective breechblock trunnions, the

ential channel 240 in the bushing. The outer face of the housing 24 is provided with suitable recesses 21 to permit use of a spanner wrench in adjusting the tension of the spring 18, and circular notches 28 in the upper circumference of said face to receive a plunger 29 actuated by spring 30 which is set in a recess 3| in the breech ring 12. The notches 28 and plunger 29 provide means securing housing 24 in position after it has been turned to adjust the tension of spring l8. Plunger 22 has a flange 29a at its outer end. This flange which extends about a portion only of the circumference of the plunger, is shaped to seat a correspondingly-shaped recess in breech ring [2, when the plunger is forced inwardly to clear notches 28. This flange thus acts to limit inward movement of the plunger. By applying a spanner to the holes 21 in housing 24 and relieveing the torsion of spring I8, plunger 29 may be forced inwardly, housing 24 may then be turned to adjust the tension of the spring, whereupon plunger 24 is permitted to move outwardly into a selected notch 28 to hold sleeve 24 in adjusted position.

The left end of the spring I8 is engaged by a clutch 32 shown in detail in Figs. 9 and 10. This clutch has a splined bore engaging the splines of shaft l5, as shown at Fig. 4. The clutch also is formed with a flange 34 forming a seat for the spring It, a recess 34a to accommodate the end of spring l8, a circumferential channel 35 in which a relieving pin may be inserted to facilitate disassembly of the breech block, and a lug 36 to engage a recess 31 in the confronting face of breech operating crank 38. A portion of crank 38 is cut away, as indicated at 44, Fig. 8, to avoid interference with the adjacent portion of bracket as the shaft and crank rotate.

The bracket 45 is fixed by cap screws 46 to breech ring i2, below and forwardly of clutch 32. The ear 41 of the bracket has a vertical threaded bore in which relieving pin 40 engages. The upper end of the bore is counterbored to receive a flange 49 on the pin and limit downward movement of the pin. An operating head 50 is pinned at 52 to the lower end of pin 40 for turning the same. Normally, that is, when the parts are as shown at Fig. 4 and with the breechblock closed, the tapered upper end of pin 49 is a little below and out of contact with the adjacent end wall of groove 35 in clutch element 32. Under these conditions, the torque of spring 18 is exerted between housing 24 and crank 38, through clutch element 32 and the engagement of lug 36 in recess 31, as previously explained. Furthermore, as the shaft l6, crank 38 and clutch 32 are rotated in lowering the breechblock the groove 35 of clutch element 32 moves along the end of pin 40 without contacting the same.

When it is desired to disassemble the parts, pin 40 is turned to move its tapered end into engagement with the end wall of groove 35. From Fig. 4 it will be noted that by this movement of the pin, the torsion of spring [8 is transferred from shaft It to pin 40, thus making it easy to Withdraw the shaft. Any transverse movement of clutch element 32 after the shaft has been withdrawn, is prevented by the housing 24 which, as clearly shown at Figs. 3 and 4, extends for substantially more than about and closely adjacent the periphery of the clutch. The coaction between in 40 and clutch element 32 is obviously equally useful in assembly of the breech parts.

We have disclosed the invention in the best construction known to us, but it will nevertheless be understood that this is purely exemplary and that changes and modifications in the construction, arrangement and combination of parts and substitution of materials and equivalents, mechanical or otherwise, may be made Without departing from the spirit of the invention set forth in the appended claims wherein We claim.

1. In a breechblock operating mechanism for a gun having a breech ring, a breechblock slidable in the breech ring between open and closed positions, a shaft journaled in the ring, operating connections between said block and shaft to slide said block in response to rotation of said shaft, said means includ ng a sleeve non-rotatably fixed to said shaft, a clutch element journaled on said shaft adjacent said sleeve, an axially separable coupling between said sleeve and element, a tor-- sion spring on said sh aft having one end anchored to said element, means anchoring the other end of said spring to the breech ring, and means operable externally of the ring to engage and rotate said element against the tension of said spring to thereby relieve the torsion of said spring otherwise exerted on said shaft.

2. A breech mechanism for guns having a breech ring and a breechblcck vertically slidable th ring, a shaft journaled in the ring transversely of the axis of the ring, means operable to slide the block in response to rotation of said shaft, said means including a sleeve non-rotatab-ly fixed to said shaft and a lever projecting from said sleeve, a clutch element journaled on said shaft adjacent one end of said sleeve, an axially separable connection between said sleeve and element, a torsion spring coiled about said shaft and having one end fixed to said element, means fixing the other end of said spring to the ring, and a pin carried by the ring and movable to engage and rotate said element against the action of said spring, whereby to relieve the torsion of said spring on said sleeve and shaft.

3. A breechblock operating mechanism for a gun having a breech ring and a breechblock movable therein between open and closed positions, means operable to close the block, said means including a shaft rotatably carried by the ring, and a sleeve fixed on said shaft, a torsion coil spring wound about said shaft, means securing one end of said spring to the ring, a clutch element journaled on said shaft, between said sleeve and spring, said spring having its other end connected to said element, an axially separable connection between said element and sleeve, and means carried by the ring movable to engage and rotate said element against the tension of said spring, whereby the torsion of said spring is removed from said sleeve and shaft.

4. The structure as recited in claim 2, said securing means comprising a housing surrounding said spring and element and to which said one end of said spring is connected, said housing being journaled in the ring, and means between said housing and ring effective to lock said housin one of a plurality of positions of rotary adjustment relatively to the ring.

5. The structure recited in claim 4, said lastnamed means comprising a plurality of circumferentially spaced notches in said housing and a plunger slidably fitting a hole in the ring parallel with said shaft, said plunger being slidable into and out of any one of said notches when the housing is rotated to bring a selected notch into position adjacent said plunger.

6. The structure recited in claim 2, said element having a radially and axially extending surface oifset from the axis of said shaft, said last named means comprising a pin threadedly carried by the ring substantially tangential of said element, said pin being turnable to bring an end thereof into engagement with said surface, ti reby to rotate said element against the tennc-n of said spring.

7. A breechblock operatin mechanism for a gun having a breech ring and a breechblock slidable in the ring between open and closed positlons, a shaft journaled in the ring on an axis normal to the bore of the gun, a breech operating lever splined on said shaft, operating connections between the breechblock and said lever, a torsion spring extending about said shaft, means anchoring said spring at one end to the ring, a clutch journaled on said shaft, said spring having its other end connected to said clutch, an axially separable lug and recess connection between said clutch and lever, and threaded pin means carried by the ring and selectively engageab-le with said clutch to relieve the tension of said spring from said lever.

WILLIAM SUMMERBELL. SAUL WEISS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 142,702 Meigs et a1 Oct. 27, 1903 1,45%{013 Tampier i- June 5, 1923 2,216,860 Summerbell Oct. 8, 1940 2,265,629 Christiansen Dec. 9, 1941 

